Thiophosphoric acid esters



i d states Patent This invention relates to certain new and useful thicphosphoric acid esters and methods for the general preparation of thiophosphoric acid esters of the following formula:

BOX

wherein R stands for alkyl radicals, R may be an aliphatic radical and aromatic radical, the residue of a thiccarbonic acid or their derivatives, for instance, a thicphene radical, a monocyclic thiazole radical, a benzothia- 3,004,980 v Patented Qct. 1 7,l91

B-position of a B -bromoethylthiol'(or thiono-thiol-) phos phonic ester can be exchanged by this way, is very surprising, since the bromine standing in fi-position of hydrojryl compounds (e.g. alcohols, phenols, and the like) cannot be exchanged under similar conditions. The reaction generally may be carried out at temperatures fromjabout 0 to about 150 C., more specifically between about and 60 C. Generally the use of inert organic solvents such as liquid hydrocarbons, alcohols, ketones, ethers and the like is preferred, to accomplish the reaction. Examples of specific useful solvents are benzene, toluene, hexane, benzine, cyclohenane methanol, ethanol, acetone, methyl-ethyl-ketone, acetonitrile, etc. To react the halo-, especially the bromo-, alkyl esters with the appropriate mercaptans, the use of acid binding agents is advantageous. Thus the reaction may be carried out by reacting an alkali salt of a mercaptane with the halide zole radical, and alkoxythiocarbonyl group and a thiocarbamyl group, X stands for O or S and Y is alkylene, particularly lower alkylene. This case is a continuation in part of our parent case, Serial No. 525,769.

- The compounds of the above type are generally valuable pesticides. Analogous substances, wherein R is an alkyl radical are used as insecticides in practice. Also various ways to obtain these alkyl compounds are known e.g. from the German Patent 830,509, wherein the reaction of salts of diesters of thiophosphoric acids with haloalkyl-mercaptans is described; another way to obtain these compounds is to react thiophosphoricor phosphoric-acid halides with mercapto-alkyl mercaptans.

It is an object of thepresent invention to provide new and useful thioland thiono-thiol-phosphoric acid esters, particularly valuable in the field of insecticides.

Another object is to provide a general method for preparing the novel compounds of the invention and analogous compounds; stillfurther objects will become apparent as the following description proceeds.

In accordance with the present invention it has now been foundthat thioland thiono-thiol-phosphoric acid etsers of the above formula and more specifically compounds of the formula l R0 s l s-or-s-rv no i in which R stands for alkyl (especially lower alkyl) or phenyl radicals, Y is a lower alkylene, particularly an ethylene chain and R is an aromatic (preferably phenyl) radical or the residue of a dithiocarbonic acid, may be obtained by reacting a B-halo-alkyl-thioL. or thiono-thiolphosphoric acid esterwith the corresponding mercaptan or dithiocarbonic acid derivative. reaction takes place in accordance with the following general scheme:

no no In those formulae R, X, Y and R have the same significance as shown before, Hal means chlorine, bromine or iodine and Me stands for a metal or generally a salt forming anion. W a t a 1 The hitherto known .thiophosphoric esters,.'e.g. those described in German,Patent'830,509 (in which R stands for e.gan alkyl radicalsuch as methyl, ethyl,.propyl, butyl or other radicals) as well as the novel compounds of the invention may be obtainedby this reaction. The fact that. the halogen,- especially the bromine atom, in

compounds. It is not absolutely necessary, however, to start from salts of mercaptaus. It is also possible to mix the mercaptans to be converted with e.g. the equivalent amount of an alkali metal alcoholate, such as the methylate or ethylate, and then to react this mixture at a slightly elevated temperature to obtain the desired S-alkylmercapto-alkyl-thiol (or thiono-thiol-) phosphoric acid ester.

Examples of especially suitable phosphoric ester reactants are the S-(bromoethyl-) 0,0-dimethyl (or the corresponding -diethyl, -dipropyl, -dibutyl, -diamyl, -diphenyl-, dicyclo-hexyl or the mixed alkyl) -thiol- (or thionothiol-) phosphoric esters. Instead of the S-bromoethyl ester, also the S-bromo-isopropyl, the S-bromo-(1,2-dimethyl-ethyl-) ester and the like may be used. In this case esters in which the S-ethyl group is further substituted by lower alkyl residues are obtained. The preparation of the bromoesters is described in copending application Serial No. 605,959, new Patent No. 2,928,863 (Le A 3215) of Gerhard Schrader, filed concurrently herewith and entitled Thiophosphoric Acid Esters and Their Production. Suitable aromatic mercaptans or derivatives of dithiocatrbonic acids to form the new compounds are e.g. phenyl mercaptan, p-chloro-phenyl mercaptan, the tolyl mercaptan, the xylylmercaptans, 3,4-dichlorophenylmercaptan, aromatic, heterocyclic mercaptans (such as 2-mercaptothiophene, Z-mercaptothiazole, 2- mercapto-benzo-thiazole etc.) dithio-carbonic acid esters such as the methyl-, ethyl propyl-, butyl-esters, etc., or dithiocarbonic acidamides such as the dimethyl-, diethyl-, dipropyh, dibutyl-amide, the piperidide, the morpholide, etc. The thiophosphoric acid esters of the present invention are valuable insecticides which exhibit partly a systemic action with living plants. They may be used against a wide range of pests such as flies, mites, aphids, etc. Usuallytheir application should be carried out in dilution or solution with solid or liquid carriers such as talc, chalk, bentonite, alcohol, water, hydrocarbons, etc. Concentrations from about 0.0001 to about 1% usually effectively kill the pests; lower or higher concentrations, however, can be used if desirable or necessary. The application may preferably be accomplished by dusting or spraying the active compounds or their compositions in the usual way for the application of phosphoric insecticides.

The following examples illustrate the present invention, without, however, restricting it thereto:

' thereto and the whole is stirred for several hours. The

salt of ethyl mercaptan is thus formed. To this suspension of the sodium salt there are added with stir- 7 obtained.

Example [I V 23 grams of phenyl mercaptan are mixed with 64 gramsof an approximately percent sodium ethylate solution. 56 grams of fi-bromoethyl-thiol-phosphorio a'c'id diethyl ester are added thereto at 35 to 40 C. and the temperature is maintained for a further hour. I action product is mixed with ether, shaken out with 70 ml. of water, dried, the ether is evaporated,fand the residue fractionated. The ,B-phenylmercapto-ethyl-thiolphosphoric acid diethyl ester boils at 137 C. at 0.01 mm. Hg. 41 grams of. the new ester are thus obtained.

. Example III The following esters may be obtained under similar conditions as described in EXample'II:

, 4-- methyl-phenyl-mercapto-ethyl-thiolfphosphoric acid diethyl ester, B.P. 148 C./0.1 mm. Hg; 4 chloro-phenyl-mercapto-ethyl-thiol-phosphoric acid diethyl ester, Bl. 163 C./ 0.2 mm; Hg; 3,4-dichloro-phenyl-mercapto-ethyl thiol-phosphoric, acid .di-ethyl ester, B.P'. 171 C./0.2 mm. Hg.

Example I V H30 0 we n. g v

H30 7 Cz s" 3'0fgrams of 'dimethylamino dithioearbamic' aeicf sodium salt are'suspended in 300 ml. of acetone 56 gramsof fi-bromoethyl-thiol-phosphoric acid ethylester are added thereto with stirring at SO-to 55 C. and the temperature is maintained for an hour. The sodium'bromide thus formed is filtered oif with suction and the solvent is removed from the filtrate by distillation. In this way 50 grams of the new mercapto phosphoric acid ester is obtained. The esterdecompose's even in high vacuum 0ndistillation. The new product is a pale yellow, barely water-soluble The re-.

Example VI 0 00,11. HO--C:H4SC:H4SP

00in. 28 grams o p hydr'oxy'ethyl mereaptanare dissolved in 64 grams-or an: a proximately to'percent' ethylat'esolution; To this solution are addedwith' stiiri'rig at 30 C. 56 grams of fl-bromoethyIFthiol-phos'phorie acid ethyl esters After ashort time bromide" is separated with a clear heat etfeet. The aforesaid temperature is maintained for a fiurther l5 n1'inutes, the sodium bromide formed is then filtered off with suction, the alcohol is evaporated from the filtrate, andthe residue is taken up with a little ether. The ethereal solutionis washed with a little water, driedrand fractionated. 33 grams of diethyl-thiol-fi-hydroxy-ethyl-thioethyl-ester of B.P. 140 C./0.01 mm. Hg are obtained. The new ester is an almost odorless, pale yellow, barely water-soluble oil.

Example VII s o. omnicgs"-o'.n;s-1= V I N/ OCzHf; 33.5 grams of 2-rnercaptobenzd-thiazole aredissolved' in 125 ml. of acetone and 64 grams of an approximately 10 percent sodium ethylate solution. To this solution are added with stirring at C. 56 gramsof p-bro'me ethyi thiol-phosphoric acid diethyl ester dissolved in '75 m1. of acetone. The indicated temperature is maintained for about /2 hour, the solution is filtered with suction from the sodium bromide formed; and the solvent-is distilled on from the filtrate. The residue is'taken up in 100' m1. of chloroform; vvasli'ed with a little Water; dried andfreed from the solvent-in vaeuo. -52 grainsof the diethylphosphoric acid fl-2mercapto-benzo thiazyl-ethyl ester having a B. P. 1 90 C. at 0.05m'ni. H-g are obtained. The new ester is a yellow, barely soluble oil.

Example VIII- S OGJH; ll/ Cz sSOHzCH:'SP

V QCI s 15 gralms of ethyl mercapt'an a're dissolved in 15" cc. of ethanol. Thissolutionis" mixed with 1000c; of ethanol,

" containing 0.2 mol of sodium ethylate, at 25 6. While stirring, there are added at 40 C. 60 grams of S-'(p-bro moethyl)-thiono-thiol-phosphoric acid -0,0-diethyl ester, dissolved in 60 cc. of absolute ethanol. The reaction mixture has to react neutral after standing at 40 C. for a furtherhou'r'. Then; th'e'solution is cooledg filter'e'd from precipitated sodium bromideand the ethanol is distilled off: The residue is taken up ether threetimes. This solution is washed -with' water and then dried over sodiumsulfate After evaporating the ether the crude ester is distilled-in vacu'oi There are obtained 38 g. ofth'e hoilin'g'point' at*0.01

Example IX 7 V 7 S OC Hg I v 1? 002 15; 20 gra1n's or n-But l mercaptsnasedissolved 11 20 ccl of eth'anolz This solution is combined: with moment: 0.2 mol of sodium ethylate containing ethanol at 25 .As described in Example 1 (SO grams of S-(fl-bromoethyL) thiono-thiol' -phosphoric acid diethyliester: in 60 ccLetha-no1- are added while: stirring" at 40 C. The reaction mixture should react neutral after one further hourofreactiom at this temperature The furthenrecovering": process mayo'ut aceording 'ttiflxmnple h tained 39 g. of S-(n-butyl mercapto-ethyl)-0,0-diethylthiono-thiol-phosphoric acid of the boiling point 107 at 0.01 mm. Hg.

Example X B OCi 22 grams of thiophenol are dissolved in 22 cc. of ethanol and further added to a sodium ethoxide solution as described in either Example 1 or 2. 60 grams of S-(pbromo-ethyl-)-0,0-diethyl-thiono-thiol-phosphoric acid are added following the same procedure of Examples 1 or 2. After standing for one hour the reaction mixture reacts neutral. The reaction product, S-(phenyl mercaptoethyl-)-0,0-diethyl-thionothiol-phosphoric acid, is isolated following the description of the previous examples. There are obtained 41 grams of the boiling point 128 at 0.02 mm. Hg. The ester is slightly colored and insoluble in water.

Example X1 grams of ethyl mercaptan are dissolved in 15 cc. of methanol. This solution is mixed with 100 cc. of methanol, containing 0.2 mol of sodium methylate at C. While stirring there are added slowly 55 grams of S-(B- bromoethyl-) 0,0-dimethyl-thiono-thiol phosphoric acid, dissolved in 60 grams of methanol at a temperature of 35' C. After one further hour standing at this temperature the reaction mixture has to react neutral. After recovering the reaction product according to the description given in the previous examples there are obtained 20 grams of S-(ethylmercaptoethyb) 0,0-dirnethyl-thionothiol phosphoric acid of the boiling point 78 at 0.01 mm. Hg.

6 I claim: -1. A compound of the general formula ROS in which R stands for a lower alkyl radical and R stands for a member selected from the group consisting of a thiophene radical, a monocyclic thiazole radical, a benzothiazole radical, an alkoxythiocarbonyl group and a mic carbamyl group.

2. A compound of claim 1 wherein R is a thiophene radical.

3. A compound of claim 1 wherein R is a monocyclic thiazole radical.

4. A compound of claim 1 where R is a beamthiazole radical.

5. A compound of claim 1 wherein R is an alkoxythiocarbonyl group.

6. A compound of claim 1 wherein R is a thiocarbamyl group.

References Cited in the file of this patent UNITED STATES PATENTS 2,565,920 Hook et al Aug. 28, 1951 2,571,989 Schrader Oct. 16, 1951 2,597,534 Schrader May 20, 1952 2,793,221 Fancher May 21, 1957 FOREIGN PATENTS 850,677 Germany Sept. 25, 1952 540,904 Belgium Sept. 15, 1955 542,600 Belgium Nov. 30, 1955 215,014 Australia July 26, 1956 947,369 Germany Aug. 16, 1956 OTHER REFERENCES Ritchters Organic Chemistry, Vol. II, P. Blakistons Sons & Co., Philadelphia, p. 210 (QD 251 R 54 E) (1922).

Richter: Texbook of Organic Chemistry, John Wiley & Sons, Inc., New York (1938) p. 258. 

1. A COMPOUND OF THE GENERAL FORMULA 